An electronic module generally comprises a printed-circuit board to which electronic components are soldered.
Current manufacturing processes comprise the steps of placing the solder on the board, generally in the form of a paste, of putting the components in position on said board and of melting the solder by passing the board though a reflow oven. This step of melting the solder is commonly referred to as the component soldering step. The presence of bulky components on the board or concentrations of components in certain zones of the board result in temperature gradients in the board, that is to say the various zones of the board do not reach the set temperature of the reflow oven at the same time. These temperature gradients generate thermal stresses both on the board and on the components that have been heated most. The thermal stresses may result in a deterioration in performance and premature aging of the components. To avoid or limit these temperature gradients it is necessary to produce, depending on each type of module, specific thermal profiles of the reflow oven that prove to be tricky to control.
The bulkiest components also limit the heat exchange for optimally melting the solder, by masking the smallest components or smallest parts thereof.
Furthermore, these bulkiest components mask other components and prevent these masked components from being checked visually.
Moreover, with the known processes using a reflow oven, passage through the reflow oven limits the maximum height that the components can have.
In addition, the appearance of new standards relating to the composition of the solder run the risk of raising the melting temperature of the solder. There is a risk of this temperature rise increasing the thermal stresses experienced by the components. It will then be necessary, in order to produce the bodies of the components, to use improved high-performance plastics in order to withstand this temperature without being damaged. Certain components whose performance may be affected by excess heat will also have to be improved.